CONCLUSIONS: We have demonstrated for the first time to our knowledge that PfSPZ Vaccine can protect against a 3-week heterologous CHMI in a limited group of malaria-naive adult subjects. A 3-dose regimen protected against both 3-week and 24-week homologous CHMI (87% and 57%, respectively) in this population. These results provide a foundation for developing an optimized immunization regimen for preventing malaria.

TRIAL REGISTRATION: ClinicalTrials.gov NCT02215707.

FUNDING: Support was provided through the US Army Medical Research and Development Command, Military Infectious Diseases Research Program, and the Naval Medical Research Center’s Advanced Medical Development Program.